Tau-Leptons and ..... errr..... stuff?? (25)

1 Name: Crazed Otaku 2005-07-22 04:21 ID:Heaven

Could someone post what exactly Tau-leptons are? I know that they are part of the Lepton family of Fermions along with Neutrinos and Muons (I could be wrong.... my memmory sucks). Also, what is it's roles in Quantum Chromodynamics. It must have something yo do tith quarks and glutons, right?????? (God I'm stupid!) But then how does it fit with Prrbation theory (or was it the W-particle)or does it have absultly nothing to do with it... god I'm confused!
Baka, baka, baka, baka, baka, BAKA!!! >o<

PS - Whats all this that I hear about neruenos being Tachyons????

Has heart attack and dies
(RIP Idiot, RIP)

2 Name: !WAHa.06x36 2005-07-22 12:24 ID:U+JwMdDb

Tau leptons are part of the lepton family, which contains electrons, muons and tau leptons. Every leptop has a corresponding neutrino: electron neutrinos, muon neutrinos and tau neutrinos. Leptons are affected by the electromagnetic and weak nuclear forces, while neutrinos (having no charge) are only affected by the weak nuclear force. Quarks are unrelated - they are largely governed by the strong nuclear force. They do exist in pairs in a family of three too, though - up and down, strang and charm, top and bottom.

Why are you having a fit on the internet about tau leptons anyway?

3 Name: Crazed Otaku 2005-07-22 14:55 ID:Heaven

Becuse I was trying to find out info about the Lepton family of Fermions.
Not only that but as a stupid high schooler during school vacation I'm a fish-out-of-water. (No teachers who I can contact 'cept mt Global teacher who I discuss major global issues with... why?... whe called home once to yell at me for not bringing my HW.... one word.... Caller ID, lol)

I'm sorry for asking any stupid questions, but my memory is horrable.

Ah, also.... what makes it diffrent than other parts of the lepton family (muons & neutrinos)
cuz so far I know that Neurenos are super light w/ little mass and interact via weak-force (Thus the reason why I had the W-particle and prebation theory on the top of my head). And Muons according to the standerd model are seme-stabel particles with a 1/2 spin.

PS - I'm soooooo happy that I finnaly have a place to ask my questions! I once went to a QM board but they were mostly collage+ and I really didn't want to be looked down at for stupid questions. Also, since all matter consists of ether quarks or leptons. Both interact by xchangeing quana as described as the maxwell and Yang-mills feilds. (I could be wrong thogh) It would probally be basic for them, right?

4 Name: Mad Scientist 2005-07-25 12:50 ID:I78h+M9J

Posting in legendary phlegm.

5 Name: - 2005-07-25 13:15 ID:Heaven

Lepton tea, anyone?

6 Name: !WAHa.06x36 2005-07-25 20:30 ID:6IFhuQ/s

The lepton family actually consists of pairs of particles: electron and electron neutrino, muon and muon neutrino, and tau lepton and tau neutrino. The difference between the electron, muon and tau lepton is basically mass (the electron is light, the muon heavier, the tau really heavy). The neutrinos are all very light (for the longest time it was uncertain if they had any mass at all, but it seems they probably do), and uncharged. The pairs are sometimes called "generations", and interactions mostly happen only between particles in the same generation.

Also, the massive leptons (the muon and tau) are unstable and will decay to their lighter siblings, emitting neutrinos in the process I think a muon decaying into an electron will emit a muon neutrino and an anti-electron neutrino, but don't quote me on that, I'm running out of material I can remember from the particle physics class I took earlier this year. Neutrinos are emitted in most processes that involve the weak nuclear force. They make sure that conservation laws are obeyed, since the weak nuclear reactions would otherwise not conserve spin properly.

7 Name: Crazed Otaku 2005-07-26 02:04 ID:Heaven

Thanks!! I get it now. Thanks, thanks! (*≧∇≦)ノ

Also They found out that they had mass in the Super-Kamiokande experement. ^o^

8 Name: Sling!XD/uSlingU 2005-07-26 03:51 ID:Heaven

My theory is that anything that moves at the speed of light has no mass whatsoever.

9 Name: Crazed Otaku 2005-07-26 05:42 ID:Heaven

Can anything even move at the speed of light? I know that if you go faster space-time warp so you really cannot go faster than light but as fast?? Hmmmmmmm...... (; =o=)ノ

Someone please leave a comment in my blog... the fact that no one is commenting is pissing me off.

10 Name: ヽ(`Д´)ノ!pjFg/WY9Ck 2005-07-26 12:17 ID:Heaven

No. Blogs suck. 4-ch is quiet as crap.. I think there must be like, 4 people looking at this page per week.

11 Name: Sling!XD/uSlingU 2005-07-26 21:07 ID:Heaven

At c speed, an object will have infinite mass, so it's not possible... unless you have a Star Trek warp drive. :)
"Warp drive is a technology that allows space travel at faster-than-light speeds. It does this by generating warp fields to form a subspace bubble that envelops the starship, distorting the local spacetime continuum and moving the starship at velocities that exceed the speed of light."
Basically, an anti-Doppler effect forcefield.

Derivative technology would be useful on supersonic jets... no more shock waves.

12 Name: !WAHa.06x36 2005-07-26 23:15 ID:6IFhuQ/s


If neutrinos have mass, as it seems, then they do not move at the speed of light. However, they move very close to it, since their mass is very small.

13 Name: Sling!XD/uSlingU 2005-07-27 14:44 ID:Heaven

That doesn't compute for me... an infinite mass is an infinite mass, no matter how small the mass is...

What was the experiment used to prove neutrinos have mass?

14 Name: Sling!XD/uSlingU 2005-07-27 14:50 ID:Heaven

never mind - I found the reference.

15 Name: Sling!XD/uSlingU 2005-07-27 15:02 ID:Heaven

"The problem with this is that the neutrino masses are implausibly smaller than the rest of the known particles (at least 500000 times smaller than the mass of an electron), which, while it does not invalidate the theory, is not very satisfactory."

16 Name: !WAHa.06x36 2005-07-27 22:08 ID:6IFhuQ/s

Oh, they've got it squeezed below one electron volt? Some homework I did was the approximation for it being less than 15 eV...

17 Name: Sling!XD/uSlingU 2005-07-28 17:19 ID:Heaven

So, at what speed does a neutrino travel? "Close to c" isn't a very scientific number.
'kay, zooming around a couple of scientific websites, it seems that no one knows. They assume it's slower because it has (most probably) a mass.

18 Name: !WAHa.06x36 2005-07-28 23:41 ID:6IFhuQ/s

Yes. it's nearly impossible to measure since it's so hard to detect neutrinos. People have been hoping to spot a supernova just as it erupts and then immediately measuring the neutrino flux from it to see if the the neutrinos are delayed in relation to the photons or not. Well, now that it's been mostly agreed that they have mass, the more interesting thing is how long the delay would be.

19 Name: Sling!XD/uSlingU 2005-07-29 15:03 ID:Heaven

I dunno... How can they be sure that that photon and that neutrino were emitted at the exact same time from the supernova?

Why don't they take an accelerator and shoot a couple of neutrinos and measure the speed at the receiving end? There is no accelerator that can generate a neutrino?

20 Name: !WAHa.06x36 2005-07-30 18:39 ID:6IFhuQ/s


The process of supernova collapse is fairly well-known, so we can tell when the peaks of photos and neutrinos should occur. I can't say for sure that they happen at the exact same time, but the initial implosion is a rapid enough event that you can probably assume it is.

There are currently experiments underway to generate neutrinos and directing them at a detector half a continent away. That much is possible, but what is not possible is measuring the speed of the neutrino as it arrives. The only process we have for detecting neutrinos is having them induce reverse beta-decay in atomic nuclei (well, that's the only one that I know of, at least). This will tell you that a neutrino arrived, but not its speed.

Measuring the flight time from creation to detection might work, but I doubt we have the capability to produce enough neutrinos in a short enough pulse (we're talking nanoseconds, probably) to be able to measure the tiny difference from c of their speed.

21 Name: Sling!XD/uSlingU 2005-07-31 02:32 ID:Heaven

Neutrinos can go thru anything. One could envision a neutrino shooter on one side of the planet, and the receiving end located at the other side, shooting thru the planet core. Hopefully that should be enough of a distance?
I would put a camera coupled with a precise clock to record the scintillations at the receiving end.
But I dunno if they can shoot neutrinos with enough precision to arrive into that pool (of mineral oil, that they use to detect neutrinos).

22 Name: !WAHa.06x36 2005-07-31 18:00 ID:6IFhuQ/s

They already do that, after a fashion. Not right through the earth, but at a detector far enough away that the neutrino beam goes through the ground all the way there. The problems is, you can't focus a neutrino beam, and there is no method for producing neutrinos in just one direction. What you do is accelerate the particles that will emit neutrinos to very high speeds, so that when they finally do emit neutrinos, they already have a high momentum in one direction. This probably doesn't create a very focused beam, though. This also means you have messed with the speed of them already.

Actually, I guess you might be able to measure their speed by measuring the spread of the beam. This would either require a mobile detector or an emitter that can be aimed in different directions. I don't think either is very likely to be built any time soon.

23 Name: Sling!XD/uSlingU 2005-07-31 23:09 ID:Heaven

What about muon radiography?
Doesn't that detect the spread?

24 Name: !WAHa.06x36 2005-07-31 23:48 ID:6IFhuQ/s

Muons are charged, and therefore almost trivially easy to detect, at least in comparison to the uncharged neutrinos. The reason they actually do pass right through the earth is that they hardly interact with matter at all, and that's what a detector is - a piece of matter for the particles to interact with. The neutrinos don't do it, though. Which means you need huge amounts of particles and huge, hyper-sensitive detectors to detect the vanishingly small number of particles that do interact.

25 Name: Sindri 2005-08-02 21:23 ID:XKRqNhSz

Personally I don't think we have accurate enaugh technology in existence, when dealing with such short times. There is always that theoretical LAG.

Oh and some juxtaposing here:

Shooting an uncharged neutrinos is equal to throwing a rock trough the air, very unlikely of "hitting" anything.

Name: Link:
Leave these fields empty (spam trap):
More options...